Apparent autosomal recessive inheritance in families with proximal spinal muscular atrophy affecting individuals in two generations
- Bonn Univ. (Germany); and others
With the evidence that deletions in the region responsible for childhood- and juvenile-onset proximal spinal muscular atrophy (SMA) are on chromosome 5 it is now possible to confirm autosomal recessive inheritance in most patients (denoted {open_quotes}SMA 5q{close_quotes}). Homozygous deletions in the telomeric copy of the survival motor neuron (SMN) gene can be detected in 95%-98% of patients with early-onset SMA (types I and II), whereas as many as 10%-20% of patients with the milder, juvenile-onset form (type III SMA) do not show deletions. In families with affected subjects in two generations, it is difficult to decide whether they are autosomal dominantly inherited or caused by three independent recessive mutations (pseudodominant inheritance). Given an incidence of >1/10,000 of SMA 5q, patients with autosomal recessive SMA have an {approximately}1% recurrence risk to their offspring. Although the dominant forms are not linked to chromosome 5q, pseudodominant families can now be identified by the presence of homozygous deletions in the SMN gene. 5 refs., 1 fig., 1 tab.
- OSTI ID:
- 508235
- Journal Information:
- American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: 5 Vol. 59; ISSN AJHGAG; ISSN 0002-9297
- Country of Publication:
- United States
- Language:
- English
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